INTRODUCTIONThere has been a lot of research into choline over thepast few decades. It is a vitamin-like nutrient that takespart in many physiological processes and has a widerange of physiological functions [1, 2].Choline is ingested with food as part ofphosphatidylcholine or formed endogenously. Thehuman need for choline is met mainly through food.Its adequate daily intake is 425 mg for women and 550mg for men, but not more than 3.5 g/day [3]. Metabolicpathways for the conversion of dietary choline and itsendogenous synthesis are genetically heterogeneous.This determines individual sensitivity to a deficiency ofcholine [4, 5].Choline has a significant effect on the developmentand functioning of the nervous system. As part ofphosphatidylcholine, it participates in the construction,stabilization, and repair of cell membranes, includingneurons. As a component of sphingolipids, it myelinatesnerve fibers [6, 7]. As a precursor of betaine (a methylgroup donor), choline is a factor in epigenetic regulationof gene expression during neurogenesis [8, 9]. DNAmethylation is a dynamic process that can modulate theexpression of genes that regulate synaptic plasticity.Since neurogenesis continues throughout life, dietaryintake of choline as a source of methyl groups canaffect cognitive functions at various stages of ontogenesis[10].Copyright © 2021, Tarasova et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 InternationalLicense (http://creativecommons.org/licenses/by/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix,transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license.Foods and Raw Materials, 2021, vol. 9, no. 2E-ISSN 2310-9599ISSN 2308-4057398Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405Our special interest is in choline as a precursor ofacetylcholine, the most important neurotransmitterof the central and peripheral nervous system.Cholinergic systems of the brain have been in thecenter of neuroscientific and medical research due totheir importance for cognitive functions and motorskills [11–14]. The influence of choline, eitheringested or synthesized endogenously, on the effectsof cholinergic neurotransmission is determined by alarge number of genetic and epigenetic factors. Thesefactors include enzyme systems that transport cholineto the presynaptic terminals of neurons, the synthesisof acetylcholine from choline and acetylcoenzyme Aand its inactivation after its use in synapses, as well aslocalization and activity of muscarinic and nicotiniccholinergic receptors. Therefore, it is difficult tointerpret experimental data on the relationship betweenexogenous choline and the effects of acetylcholine.The effects of choline on the nervous systemhave also been extensively studied. For example, itsdeficiency has a negative impact on the intrauterinedevelopment of the nervous system. Some studieson animals found that choline-enriched nutrition ofpregnant females improved the cognitive functionsof their offspring at various stages of ontogenesis andslowed down age-related involution. Its most pronouncedeffect was found in the study of learning and spatialmemory in rodents using the Morris water maze, whichindicated the involvement of hippocampal neurons [10].However, the studies on humans, which examined theeffect of a choline-fortified diet for pregnant women onthe development of their children’s cognitive abilities,produced conflicting data [15–17].Another area of choline research is itsneuroprotective effect and impact on cognitive functionsin adults. Pharmaceutical choline-containing drugs areoften prescribed for pathologies of the nervous system.The neuroprotective effects of choline alfoscerate andcytidine-5’-diphosphocholine (citicoline) have beenproven in treating cognitive impairment associatedwith trauma, vascular disorders, or neurodegenerativediseases [18–21]. The studies of choline effect oncognitive functions of healthy individuals in postnatalontogeny have yielded mixed results. For example,memory tests on 1391 adult men and women withoutcognitive impairment revealed a positive effect ofcholine consumption, with similar results found forcognitive tests on 2195 people aged 70–74 [22, 23].Knott et al. examined the effect of a single dose ofciticoline in low and medium concentrations. Theyfound that the effect was determined by the initial levelof choline, i.e., the subjects with initially low levels ofcholine had improved cognitive functions after citicolinetreatment [24].According to another study, choline bitartrateimproved the accuracy (rather than the time) ofvisual-motor task performance in students [25]. Apositive relationship was found between the plasmacholine content in 15-year-olds and their schoolperformance [26]. Other researchers, however, did notobserve a positive effect of short-term choline bitartratetreatment on the memory function of students [27].Studies on school and college students are especiallyrelevant. Childhood and adolescence are the periodsof life when the morphofunctional maturation of thenervous system is combined with intensive cognitiveactivity during schooling. Of paramount importancetherefore is nutrition that satisfies the plastic andfunctional needs of the nervous system. Choline is oneof such nutrients. However, more research is needed toclarify the relationship between choline and cognitivefunctions in different age groups, including students.We should also mention a potential negativeeffect of high choline intake on human health. Thisproblem has been widely discussed in recent years dueto the existence of choline metabolic pathways withthe participation of intestinal microflora. A certaincomposition of intestinal microbiota produces a largeamount of trimethylamine (TMA), which is absorbedby the epithelium, entering the liver through the portalvein, where it is converted into trimethylamine N-oxide(TMAO). The cumulative effects of TMAO are currentlyassociated with the risk of atherosclerosis, insulinresistance, stomach and intestinal cancer, as well askidney pathology [28–30]. Therefore, increasing cholineintake should be recommended to adults with caution.We aimed to expand our awareness of exogenouscholine effect on psychophysiological functions underincreased nervous stress. For this, we set the followingobjectives:– assessing levels of choline intake in universitystudents;– analyzing the relationship between choline intakelevels and psychophysiological characteristics;– studying the effect of choline supplementation on thefunctional indicators of the central nervous system instudents in the pre-exam period.STUDY OBJECTS AND METHODSStudy design. First, we formed a cohort of 87 studysubjects (13 males and 74 females) aged 19 from the1st- and 2nd-year students of the Department of SocialWork and Psychology at Kemerovo State University(Kemerovo, Russia) and obtained their informedwritten consent to participate in the study. All the studysubjects were surveyed by questionnaire to assess theirdietary choline intake. In addition, they underwenta psychophysiological examination to assess theirneurodynamic and cognitive functions.Next, the 2nd-year students were divided into acontrol and an experimental group, 20 people each(4 males and 16 females) by pairwise selection basedon mechanical memory. The experimental group took amono-component dietary supplement “Choline 350 mgVegetable Capsules” (Solgar, USA). The supplement wasregistered under No. RU.77.99.11.003.Е.004764.10.18of 29.10.2018 in the Customs Union’s Register of StateRegistration Certificates. Choline was taken for one399Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405month, one capsule twice a day with a meal. At the endof the intake period, both groups underwent anotherpsychophysiological examination.Finally, the data were statistically processed andanalyzed.Choline determination methods. Food frequencyquestionnaire (FFQ) was used to determine thefrequency of consumption of choline-containing foodsand to estimate the absolute daily intake by portionsize [26]. The survey followed the Russian guidelinesI.The questionnaire included foods with a cholinecontent of at least 10% of the daily intake per 100 g.It also listed dairy products (milk, kefir) which had acholine content of 5–8% of the daily intake per 100 g,but could be consumed in fairly large amounts. Thesubjects were surveyed in a group, with the interviewergiving explanations about the questionnaire. Therespondents were asked to estimate the frequencyof consumption of the listed products during the lastmonth, as well as indicate the approximate size of theportions. Then, we analyzed the responses to determinethe approximate amount of choline intake usingavailable sources [31, 32] and ranked the results by thequartile method.Methods for studying psychophysiologicalfunctions. The neurodynamic and cognitive indicatorswere determined with the psychophysiological complex“Status PF”II. The testing was carried out in a groupin the university computer classroom on Tuesday andWednesday mornings before classes with minimumextraneous irritants. Prior to the testing, we explainedits meaning and significance in order to form a positiveattitude among the study subjects. The tests that weselected did not require significant mental strain or muchtime to perform. In particular, we used the followingwell-known diagnostic tools.The latent period of a simple visual-motor reactionis the most common psychomotor indicator that reflectsthe rate of excitation along the reflex arc and, therefore,the excitability of the central nervous system. This isa rather labile indicator that adequately characterizesits functional state. The general simple visual-motorreaction time is determined by the subject’s anatomicalfeatures of the sensory system, nervous processes,psychophysiological state, and the motor-coordinationpotential. The subjects were asked to press a key on thecomputer keyboard as quickly as possible in responseto a light stimulus. The average time of a motorreaction (ms) was determined after 30 light stimuli withvarious random intervals.I Martinchik AN, Baturin AK, Baeva VS. Razrabotka metodaissledovaniya fakticheskogo pitaniya po analizu chastoty potrebleniyapishchevykh produktov: sozdanie voprosnika i obshchaya otsenkadostovernosti metoda [Developing a method to determine nutritionby the frequency of food consumption: creating a questionnaireand assessing the method’s reliability]. Problems of Nutrition.1998;67(3):8–13. (In Russ.).II Ivanov VI, Litvinova NA. Programma dlya EHVM “Otsenkapsikhofiziologicheskogo sostoyaniya organizma cheloveka (StatusPF)” [Computer program “Assessment of the psychophysiologicalstate of the human body (Status PF)”]; № 2001610233. 2001.The latent period of a complex visual-motor reactionreflects the time spent on analyzing information in theintegrative-triggering cortical zones and making adecision about how to respond. The subjects were askedto react to a red signal with their right hand, to a greensignal with their left hand, and not to react to a yellowsignal. The average time of a motor reaction (ms) wasdetermined after 30 light stimuli.Functional mobility of nervous processes wasdetermined by the method of Khilchenko (1958)modified by Makarenko et al. (1987). The level offunctional mobility is an indicator of neurodynamicconstitution that does not depend as much on theactual functional state of the central nervous systemas the simple and complex sensorimotor reactions.This method is based on a complex visual-motordifferentiation reaction in the feedback mode. Incontrast to the previous method, the intervals betweensignals depended on the correctness of motor reactions,decreasing by 20 ms after a correct reaction andincreasing after an incorrect one. The test included120 standard stimuli. The test time (s) was a quantitativelevel of functional mobility of the subject’s nervousprocesses – the less time it took to do the test, the moreaccurate the responses were. The accuracy of responseswas determined by the rate of changes betweenexcitation and inhibition, that is, the functional mobilityof nervous processes.Balance of the nervous system in response a movingobject reflects the relationship between excitatory andinhibitory processes in the cerebral cortex. This methoddetermines the accuracy of visual-motor reaction to anobject moving at the same speed in a circle. When theobject overlapped the marker on the circle, the subjectshad to press a key and “stop” it, with the time ofdeviation between the object and the marker recorded upto 1 ms. The subject’s reaction was considered accurateif the deviation was within ± 5 ms. We recorded thenumber of accurate reactions, anticipatory and laggingreactions (total and average), as well as the averagedeviation time.Short-term visual memory is a phase of imprintingcharacterized by a short storage of a limited number ofobjects in memory. The stimuli on the monitor screenincluded two-digit numbers (Ebbinghaus method),syllables (Luria method), and unrelated words (Lesermethod). They were presented one at a time for 1 s withan interval of 2 s. The capacity of short-term memorywas determined by the number of correctly reproducedstimuli immediately after presentation.Attentional capacity was determined by themaximum number of simultaneously perceived objects.The subjects were shown a lined field (5 by 5), withobjects (crosses) randomly located in the cells. Withevery exposure, the number of objects increased by one.After a 500 ms exposure, the objects disappeared andthe subjects had to locate them on the field. Attentionalcapacity was determined by the maximum number ofcorrectly located objects, expressed in points.400Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405Attention concentration was assessed with theSchulte table presented on the monitor screen. Thesubjects were to indicate the numbers from 1 to 25 inascending order. The time taken to complete the test wasan indicator of concentration. The less time one spent,the higher their attention concentration.Attentional set-shifting was assessed with a redand black Schulte-Gorbov table. The subjects wereinvited to indicate black numbers in ascending orderand red numbers in descending order: 1 – black,24 – red, 2 – black, 23 – red, 3 – black, etc. The timetaken to complete the test was a measure of attentionalset-shifting (the less time, the better the indicator).Attention stability was determined with a computerversion of the dot cancellation test. The subjects wereasked to look through lines of letters in the table andmark the given four letters for 4 min. The test assessedthe speed of performance (number of letters viewed)and its accuracy (number of errors), with their ratiocalculated as the total productivity index.The HAM (health, activity, mood) testIII was usedfor the students’ additional self-assessment of theirfunctional state. The questionnaire had 30 pairs ofsubjective characteristics with opposite meanings (forexample, “funny-sad”, “slow-fast”, etc.). The subjectswere asked to indicate their current state on a scalebetween these poles. The neutral state was marked as“0” and the extreme (most pronounced) state as “3”(both poles). The points were added up for each scale(health, activity, and mood).Statistical processing was carried out in Exceland Statistica 6.0. Mean values and standard errorswere determined for all the indicators under study. Inaddition, we performed the analysis of histograms andthe percentile analysis. Normality of the distributionwas measured by the Kolomogorov-Smirnov test. Dueto the small size of our sample, most indicators did notIII Doskin VA, Lavrentʹeva NA, Miroshnikov MP, Sharay VB. Testdifferentsirovannoy samootsenki funktsionalʹnogo sostoyaniya[A test for differentiated self-assessment of the functional state].Voprosy Psychologii. 1973;19(6):141–145. (In Russ.).have a normal distribution. Therefore, we applied theMann-Whitney test to compare two groups and themedian test for multiple comparisons. The Wilcoxonrank test was used to assess changes in indicators. Theχ2 test measured the statistical significance of differencesin percentage ratios (P < 0.05). Spearman’s correlationanalysis was also applied.RESULTS AND DISCUSSIONThe food frequency questionnaire (FFQ) resultsshowed that the approximate level of choline intakewith the products included in the questionnaire rangedfrom 100 to 900 mg per day (Fig. 1). We found that60% of the respondents had a choline intake below therecommended value (400 mg). The average cholineconsumption was 448.7 ± 50.6 mg for males and373.4 ± 21.6 mg for females, also below the recommendedvalue. Our data were generally consistent withthe results of various international studies, as reportedby Canadian authors [2]. Their review also emphasizedthat the reported low intake of total choline did nottake into account its form (water-soluble or fat-soluble)and did not always indicate its deficiency in the body.When interpreting our results, we also assumed that theactual intake of choline was higher than the level shownby the FFQ, since the questionnaire did not include allthe foods consumed by students. Yet, we had enoughgrounds for recommending that students who consumeless than 400 mg of choline per day adjust their diet byincluding foods high in choline.To study the relationship between neurodynamiccharacteristics and choline intake, the students weredivided into three groups based on the quartile analysis:a) low choline intake (under 240 mg/d), quartile 1;b) medium choline intake (240–499 mg/d), quartiles 2and 3; c) high choline intake (over 500 mg/d), quartile 4.The comparison of the neurodynamic parameters inthese groups revealed some statistically significantdifferences (Tables 1, 2).We found that the students with a high choline intakehad the best indicators for functional mobility of nervous051015202530100–200 200–300 300–400 400–500 500–600 600–700 700–800 800–900%Approximate choline intake, mg/day200220240260280300320April May Control group Latent period of a simplevisual-motor reaction, ms0.01.02.03.04.05.06.07.08.0April May April MayControl group Experimental groupAnticipatory reactionsto a moving object, ms3456789April MayControl groupApril Experimental groupPointsShort-term memory for words Short-term memory for syllables4045505560April May April MayControl group Experimental groupPointsСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April Low Attention stability, productivity3.03.54.04.55.05.56.06.5April May April MayLow choline intake High choline intakeShort-term memory forsyllables, points051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitiveFigure 1 Students distribution by choline intake (according to the food frequency questionnaire)051015202530100–200 200–300 300–%Approximate 0.01.02.03.04.05.06.07.08.0April May April Control group Experimental Anticipatory reactionsto a moving object, ms4045505560April May Control group PointsСамочувствие Активность 5.05.56.06.5memory forpoints401Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405processes and the least time of lagging reactions to amoving object.The assessment of cognitive functions producedquite unexpected results. The integral indicator ofattention stability based on the dot cancellation testwas the highest among students with a low cholineintake (Table 2). There were no other statisticallysignificant differences.We found no statistically significant correlationsbetween dietary choline intake and psychophysiologicalindicators in the sample as a whole. However, there weresignificant differences in the groups with high, medium,and low choline intake.The group with a low choline intake showedstatistically significant correlations between thecholine value and the number of anticipatory reactionsto a moving object (r = 0.46, P < 0.05), the number ofaccurate reactions (r = –0.68, P < 0.01), the averagetime of lagging reactions to a moving object (r = 0.54,P < 0.05), and the short-term memory for numbers(r = –0.31, P < 0.05). Thus, the best indicators ofpsychomotor accuracy and short-term memory werefound in students with the lowest choline intake.In the group with a medium choline intake, its dailyvalue had a negative effect on the number of accuratereactions to a moving object (r = –0.35, P < 0.05) and apositive effect on the average deviation time in the sametest (r = 0.32, P < 0.05), just as in the low choline intakegroup. We found no statistically significant correlationsbetween choline values and indicators of memory andattention in this group.The group with a high choline intake revealedan inverse relationship between choline values andthe latent period of a simple visual-motor reaction(r = –0.5, P < 0.05) and the time of completing theattention concentration test (r = –0.4, P < 0.05), as wellas a direct relationship with attention stability (r = 0.45,P < 0.05). This meant that those students who consumedmore choline in this group performed best in the visualmotorreaction and attention tests.Thus, we found that the level of dietary cholineintake had a greater effect on neurodynamic parametersthan on cognitive functions. Higher choline valuesimproved the mobility of nervous processes andaccuracy in complex visual-motor reactions. However,their effects on cognitive functions were quitecontradictory. We assumed that our results shouldbe interpreted with other factors taken into account,which affected the students’ choline intake andpsychophysiological state. Yet, these additional factorswere beyond the scope of this study.The control and the experimental groups of 20students in each were formed regardless of the cholineTable 2 Memory and attention parameters in students with different levels of choline intakeCognitive functions Choline intake Mann-Whitney U-testLow (1) Medium (2) High (3) 1–2 1–3 2–3Short-term memory (numbers), points 6.3 ± 0.4 6.0 ± 0.3 5.8 ± 0.3Short-term memory (words), points 7.13 ± 0.2 7.0 ± 0.3 7.1 ± 0.3Short-term memory (syllables), points 4.4 ± 0.4 4.6 ± 0.3 4.7 ± 0.4Attentional capacity, points 6.7 ± 0.4 6.5 ± 0.4 6.8 ± 0.4Attention concentration test completion time, s 45.4 ± 2.7 47.4 ± 2.4 45.0 ± 2.3Attentional set-shifting test completion time, s 173.4 ± 7.9 169.7 ± 5.6 167.2 ± 7.0Attention stability: total productivity index 62.6 ± 5.5 45.9 ± 5.9 48.9 ± 6.4 0.03*P < 0.05Table 3 Choline intake in the control and experimentalgroups, mg/dayGroup Medianvalue25–75percentilesControl (no choline treatment) 401 264–652Experimental (with choline treatment) 416 315–492Р (Mann-Whitney U-Test) 0.91Tаble 1 Neurodynamic parameters in students with different levels of choline intakeNeurodynamic parameters Choline intake Mann-Whitney U-test*Low (1) Medium (2) High (3) 1–2 1–3 2–3Latent period of a simple visual-motor reaction, ms 292.3 ± 8.7 303.1 ± 23.3 279.6 ± 7.3Latent period of a complex visual-motor reaction, ms 446.5 ± 17.2 444.1 ± 10.6 435.6 ± 9.6Functional mobility of nervous processes – time, s 66.6 ± 1.8 65.2 ± 1.2 63.1 ± 1.3 0.04Reaction to a moving object: average deviation fromaccurate reactions, ms29.8 ± 2.4 27.9 ± 3.3 30.4 ± 5.8Reaction to a moving object: total anticipatory reactions, ms 297.1 ± 52.0 246.5 ± 75.4 298.2 ± 62.5Reaction to a moving object: total lagging reactions, ms 513.6 ± 66.9 519.5 ± 51.4 340.4 ± 62.6 0.04 0.04*P < 0.05402Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405values. The analysis of their dietary choline intake didnot show any statistically significant differences betweenthe groups (Table 3).Thus, the control and the experimental groups, whichhad a homogeneous age and sex composition and similarcognitive indicators at the beginning of the study, werealso quite similar in choline intake.However, we identified some statistically significantchanges in their neurodynamic parameters during theobservation period (Figs. 2–5).The experimental group showed significantimprovements in the simple visual-motor reactiontimes (Fig. 2) within a month. The number ofanticipatory reactions to a moving object decreasedin the experimental group, but increased in the controlgroup (Fig. 3). The students who received cholinesupplementation had better short-term memoryfor words and syllables. However, their attentionalcapacity remained the same, decreasing in the controlgroup (Fig. 4).The HAM (health, activity, mood) method revealedthat during the second examination, the students takingcholine supplements had significantly higher indicatorsof health and activity, compared to the control group(Fig. 5). Thus, the students in the experimental groupwere in a better state of health.These changes showed that the pre-exam stress didnot affect the functional state of the central nervoussystem of students in the experimental group – in fact,it improved.Next, we divided the experimental group into twosubgroups, depending on the level of choline intake:students with choline intake below the median value(416 mg) and students with choline intake above themedian value. Thus, we could assess the effect ofcholine supplementation, taking into account thestudents’ dietary choline intake.Figure 2 Changes in the simple visual-motor reaction times(Р < 0.05)Figure 4 Changes in short-term memory and attention indicators (Р < 0.05)Figure 5 Changes in the HAM (health, activity, mood) test(Р < 0.05)700–800 800–900200220240260280300320April May April MayControl group Experimental groupLatent period of a simplevisual-motor reaction, msMayControl groupApril MayExperimental groupmemory for words Short-term memory for syllablesApril May April MayLow cholineintakeHigh cholineintake0102030405060708090April May April MayLow choline intake High choline intakeAttention stability, productivity2212 1151 533neurodynamiccognitiveneurodynamic and cognitive100–200 200–300 300–400 400–500 500–600 600–700 Approximate choline intake, mg/day0.01.02.03.04.05.06.07.08.0April May April MayControl group Experimental groupAnticipatory reactionsto a moving object, ms3456789April PointsShort-term 4045505560April May April MayControl group Experimental groupPointsСамочувствие Активность Настроение200220240260280300320340Latent period of a simplevisual-motor reaction, ms3.03.54.04.55.05.56.06.5April May April MayLow choline intake High choline intakeShort-term memory forsyllables, points051015202530143HAM-HAM-HAM- Figure 3 Changes in reactions to a moving object (Р < 0.05)100–200 200–300 300–400 400–500 500–600 600–700 700–800 800–900Approximate choline intake, mg/day200220240260280300320April May April MayControl group Experimental groupLatent period of a simplevisual-motor reaction, msApril May April MayControl group Experimental group3456789April MayControl groupApril MayExperimental groupPointsShort-term memory for words Short-term memory for syllablesApril May April MayControl group Experimental groupСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April May April MayLow choline intake High choline intakeAttention stability, productivityApril May April MayLow choline intake High choline intake051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitive051015202530100–200 200–300 300–400 400–500 500–600 600–700 700–800 800–900%Approximate choline intake, mg/day200220240260280300320April May April MayControl group Experimental groupLatent period of a simplevisual-motor reaction, ms0.01.02.03.04.05.06.07.08.0April May April MayControl group Experimental groupAnticipatory reactionsto a moving object, ms3456789April MayControl groupApril MayExperimental groupPointsShort-term memory for words Short-term memory for syllables4045505560April May April MayControl group Experimental groupPointsСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms 0102030405060708090April May April Low choline intake High Attention stability, productivity3.03.54.04.55.05.56.06.5April May April MayLow choline intake High choline intakeShort-term memory forsyllables, points051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitiveHealth Activity Mood403Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405Figure 6 Changes in the simple visual-motor reaction timesin students with choline supplementation vs. initial cholineintake (Р < 0.05)Figure 7 Changes in attention stability in students withcholine supplementation vs. initial choline intake (Р < 0.05)We found statistically significant changes inneurodynamic parameters among students from theexperimental group with a low choline intake. Inparticular, they showed a shorter simple visual-motorreaction time (Fig. 6) and improved attention stability(Fig. 7).Changes in cognitive functions indicated bettershort-term memory for syllables in all experimentalstudents, regardless of their choline intake, andimproved performance in the dot cancellation test onlyin those with a low choline intake (Fig. 8).The self-assessment with the HAM (health, activity,mood) method did not reveal any significant trendsassociated with levels of choline intake.In order to obtain more general information abouthow choline supplementation affected the functionalstate of the central nervous system, we analyzedcorrelations between different psychophysiologicalparameters throughout the study. The closerconnectedness between various neurodynamic,cognitive, and subjective indicators was regarded as asign of increased psychophysiological adaptation in thepre-exam period.Figure 9 shows changes in the number of statisticallysignificant correlations between various indicators inthe control and experimental groups. We can see a cleardifference in the number of correlations between thecontrol and experimental groups, indicating a lesserdegree of cognitive stress in the students who tookcholine supplements.Thus, we found a positive effect of cholinesupplementation on the psychophysiological indicatorsof students in the stressful pre-exam period. Yet,some of the results were quite ambiguous and evenconflicting: for example, negative correlations betweenbackground choline intake and attention indicators inboth the control and the experimental groups, or generaluselessness of choline supplementation for cognitivefunctions. As we know, a human need for choline andsensitivity to its deficiency are highly variable andgenetically determined by heterogeneous metabolicpathways of endogenous synthesis and dietary cholineconversion.Our study showed that choline supplementation canbe recommended to students, especially those with a lowconsumption of choline-rich foods.MayExperimental group3April MayControl groupApril MayExperimental groupShort-term memory for words Short-term memory for syllablesApril MayExperimental groupАктивность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April May April MayLow choline intake High choline intakeAttention stability, productivityMaycholine intake051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitiveMay April Maygroup Experimental group3April MayControl groupApril MayExperimental groupShort-term memory for words Short-term memory for syllablesMay April Maygroup Experimental groupСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April May April MayLow choline intake High choline intakeAttention stability, productivityMay April Maycholine intake High choline intake051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitiveFigure 8 Changes in short-term memory in students withcholine supplementation vs. initial choline intake (Р < 0.05)Figure 9 Statistically significant correlations betweenpsychophysiological indicators in different groups051015202530100–200 200–300 300–400 400–500 500–600 600–700 700–800 800–900%Approximate choline intake, mg/day200220240260280300320April May April MayControl group Experimental groupLatent period of a simplevisual-motor reaction, ms 0.01.02.03.04.05.06.07.08.0April May April MayControl group Experimental groupAnticipatory reactionsto a moving object, ms3456789April MayControl groupApril MayExperimental groupPointsShort-term memory for words Short-term memory for syllables4045505560April May April MayControl group Experimental groupPointsСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April May Low choline intake Attention stability, productivity3.03.54.04.55.05.56.06.5April May April MayLow choline intake High choline intakeShort-term memory forsyllables, points051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitive051015202530100–200 200–300 300–400 400–500 500–600 600–700 700–800 800–900%Approximate choline intake, mg/day200220240260280300320April May April Control group Experimental Latent period of a simplevisual-motor reaction, ms 0.01.02.03.04.05.06.07.08.0April May April MayControl group Experimental groupAnticipatory reactionsto a moving object, ms3456789April MayControl groupApril MayExperimental groupPointsShort-term memory for words Short-term memory for syllables4045505560April May April MayControl group Experimental groupPointsСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April Low choline Attention stability, productivity3.03.54.04.55.05.56.06.5April May April MayLow choline intake High choline intakeShort-term memory forsyllables, points051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitiveApril May April MayControl group Experimental group051015202530100–200 200–300 300–400 400–500 500–600 600–700 700–800 800–900%Approximate choline intake, mg/day200220240260280300320April May April Control group Experimental Latent period of a simplevisual-motor reaction, ms0.01.02.03.04.05.06.07.08.0April May April MayControl group Experimental groupAnticipatory reactionsto a moving object, ms3456789April MayControl groupApril MayExperimental groupPointsShort-term memory for words Short-term memory for syllables4045505560April May April MayControl group Experimental groupPointsСамочувствие Активность Настроение200220240260280300320340April May April MayLow cholineintakeHigh cholineintakeLatent period of a simplevisual-motor reaction, ms0102030405060708090April Low choline Attention stability, productivity3.03.54.04.55.05.56.06.5April May April MayLow choline intake High choline intake Short-term memory forsyllables, points051015202530142212 1151 5333HAM-neurodynamicHAM-cognitiveHAM- neurodynamic and cognitive404Tarasova O.L. et al. Foods and Raw Materials, 2021, vol. 9, no. 2, pp. 397–405CONCLUSIONHalf of the students had a dietary choline intakebelow the recommended value. The levels of cholineintake had a greater effect on the neurodynamicparameters than on the cognitive functions. Increasedcholine intake correlated with higher functional mobilityof nervous processes and faster reactions to a movingobject. The students who took choline supplements forone month had positive changes in the functional stateof the central nervous system, compared to the controlgroup. Besides, these changes were more pronouncedin those students who had a low intake of dietarycholine. An additional daily intake of 700 mg cholinesupplements can be recommended to students underpre-exam stress, especially those with a dietary cholinedeficiency, to improve the functional state of theircentral nervous system. However, we did not assess theeffectiveness of smaller amounts of choline. We believethere is no need for continuous choline supplementation,since current research indicates possible negative healtheffects.CONTRIBUTIONThe authors were equally involved in preparing themanuscript.CONFLICT OF INTERESTThe authors declare that there is not conflict ofinterest.